Strand guide for a continuous casting plant



Feb. 27, 1968 w, EI ETAL 3,370,642

STRAND GUIDE FOR A CONTINUOUS CASTING PLANT Filed Aug. 5, 1965 2Sheets-Sheet l a N u) N I N VEN TORS A BY ATTORNEYS Feb. 27, 1968 w.MEIER ETAL 3,370,642

7 STRAND GUIDE FOR A CONTINUOUS CASTING PLANT 2 Sheets-Sheet 2 FiledAug. 5, 1965 ATTORNEYS United States Patent 0 f STRAND GUIDE FOR ACONTINUOUS CASTING PLANT Walter Meier, Winterthur, and Armin Thalmann,Zurich, Switzerland, assignors to Concast AG., Zurich, Switzerland FiiedAug. 3, 1965, Ser. No. 476,865 Claims priority, application Switzerland,Aug. 4, 1964, 10,173/ 64 1 Claim. (Cl. 164282) ABSTRACT OF THEDISCLOSURE The strand guide system comprises a roller guide positionedbelow a continuous casting mold. The roller guide consists of a rollerguide mounting means positioned adjacent the desired course of thestrand and includes a plurality of guide roll pairs. Each of the rollpairs consists of a first and second roller spaced apart by apredetermined fixed distance and so mounted as to permit a limiteddeflection of each of the roller pairs in a direction transverse to thelongitudinal axis of the strand. By this means, proper guidance isachieved in a guide arrangement requiring less set-up time.

The present invention relates to an apparatus for continuous casting ofmetal and particularly refers to an apparatus for guiding the caststrand immediately below the mold.

In most cases a strand guide system of this kind comprises guidingelements in the form of rollers. These strand guide systems are known asroller guide systems and consist of a number of successive pairs ofrollers, the rollers of each individual pair being disposed one oppositethe other with fixed spacing between them. The sum of the distancesbetween the individual pairs of rollers gives the guide path for thestrand withdrawn from the mold, such strand being preceded by a dummybar.

Of course, this dummy bar and the following cast strand can besatisfactorily introduced, guided and delivered only if casting ispreceded by accurate setting up of the various pairs of rolls inrelation to one another allowed by setting up of the entire roller guidesystem with respect to the mold aperture and the rolls situateddownstream thereof (for example the withdrawing rolls, bending orstraightening rolls).

This setting up operation is very time-consuming particularly whencurved strands are being cast from a curved mold. Any mistakes madeduring setting up may have a disastrous effect on casting, since rolerswhich have not been set up accurately may cause the strand to breakbecause of their forces exerted on the strand or may at least result innon-uniform strand quality.

The strand guide system according to the invention obviates thesedisadvantages, to which end it comprises curved strand guiding meansconsisting of pairs of rollers where each pair is movable to a limiteddegree perpendicular to the surface of the strand S and centers ofrollers are firmly interconnected by maintaining a fixed distancebetween each other.

In this way, for example, on introduction of the dummy barself-alignment of the movable roller pairs is obtained so that exactsetting up of the roller guide system is dispensed with. During casting,the strand and the guide system adjust to one another flexibly so thatany extreme or abrupt stresses on eitheri.e. either the strand surfaceor the rollersare obviated and the strand is guided gently but firmlyalong and to the end of the guide system.

3,379,642 Patented Feb. 27, 1968 Further characteristics of theinvention can be seen below.

Two exemplified embodiments of strand guide systems according to theinvention are illustrated in the accompanying drawings, wherein:

FIG. 1 is an elevation view of a continuous casting plant using thestrand guide in accordance with the present invention.

FIG. 2 is an elevation view of a portion of the strand guide of FIG. 1to enlarged scale.

FIG. 3 is a section on the line IIIIII in FIG. 1.

FIG. 4 is a section on the line IV-IV in FIG. 1.

FIG. 5 is a section of the movable pair of rollers on the line V-V inFIG. 6, as a detail of a roller guide according to a second embodiment,and

FIG. 6 is an axial section on the line VIVI through the movable pair ofrollers of the second embodiment shown in FIG. 5.

As shown in FIG. 1, liquid metal is poured from a container not shown inaccompanying drawings, into a cooled mold K. This mold K is closed by adummy bar at its withdrawal end, reaching down to a withdrawing andstraightening aggregate A. The resulting strand S is drawn from the moldK, when the solidified skin is of sufficient strength, guided by curvedstrand guiding means positioned between mold K and aggregate A andcooled fur ther as already known.

The roller gmide system illustrated consists of three parts 2, 3, 4(alternatively they could be just two or more than three), eachconsisting of interconnected top and bottom angle-section pairs 5 and 6respectively. The detachable connection between the adjacent rollerguide system elements is by way of stays 7 and 8 which are affixed tothe top and to the bottom angle sections 5 and 6 of two adjacent parts.Another two such stays 9 and 10 are also provided at the free ends ofthe roller guide system parts 2 and 4. The same arrangement is providedon the other side of the rollers (see FIG. 4) at a distancecorresponding to the width of the roller guide system.

Bearings to receive the journals of rotatably mounted rollers 11, 12 areprovided in the stay 9; for rollers 13, 14 in stay 8; for rollers 15, 16in stay 7; and for rollers 17, 18 in stay 10. Thus, the stay mountedrollers are fixedly positioned in a predetermined distance apart.

Other pairs of rollers, for example the rollers 19 and 20, are providedbetween these fixed pairs of rollers, but are movable to a limitedextent in a direction at rightangles to the strand axis while firminterconnection is maintained between them. In the exemplifiedembodiment shown in FIGS. 1 to 3 this is achieved by the fact that thejournals of the rollers 1? on the surface forming the inner radius ofthe strand, and of the rollers 20 on the surface forming the outerradius of the strand are the pivot axes of link chains 21 and 22, therollers 11, 13, 15, 17, 19 of the pairs all being situated between theinner two chains 21 and the rollers 12, 14, 16, 18, 2%) all beingsituated between the two outer chains 22. The chains 21, 22 respectivelyhang freely between the fixed rollers 11, 13, 15, 17; 12, 14, 16, 18respectively, the outer chain 22 in each case extending in parallelrelationship to the inner chain 21 on the same side of the strand S. Thefirm distance between the two link chains 21, 22 at each end of therollers and hence the firm distance between the rollers 19, 20 of eachmovable pair is achieved by shackles 23 connecting the pivots of therollers -19, 20 forming a pair. Of course, this distance is equal to thedistance between the rollers of the fixed, i.e. non-slidable, pairs ofrollers. While this fixed distance between the rollers 19, 20, whichdepends on the strand cross-section, is maintained, the pairs of rollersare movable independently to a limited extent in a direction atright-angles to the strand axis between the immovable pairs of rollersmounted on the stays 7 to 10.

The same effect is obtained with the embodiment shown in FIGS. 5 and 6but without the use of chains. The roller guide system in thisembodiment comprises rails 32 to support the consecutive pairs ofrollers 30, 31, such rails being disposed on each side of the rollersand the longitudinal axis of the rails corresponding to the imaginarystrand axis. As in the first exemplified embodiment, the two rollers 30,31 of each movable pair are kept at a fixed distance according to thestrand size by means of shackles 33 at the ends. Between the rollers 30,31 each of these two-part shackles 33 extends through a boss 34 securedto the rail 32, so that they and the associated rollers 30, 31 areslidable at right-angles to the axis of the strand S at this placebetween a top and bottom end position. Springs 35, 36 disposed on eachside of the boss 34 in the direction of displacement between thelatterand a shoulder of the shackle 33 ensure that the rollers 30, 31are always kept in a middle position between the two end positions, butbeing displaceable independent of neighbouring pairs of rollers verticalto the strand surface between two end positions against springs withrespect to a fixed rail.

Advantageously, in the two embodiments described, the slidability of themovable pairs of rollers from the middleposition in each direction isabout 1 to 2".

All the fixed pairs of rollers could be driven in the manner alreadyknown, so that they could completely or partly act as withdrawingrollers.

Instead of rollers, the guide elements used may be in the form ofsliding elements movable vertically in relation to the strand surface.

The continuous casting machine in FIG. 1 shows a curved mold to be usedto a cast curved strand. By having a mold which is straight relative tothe axis of the strand casting a straight strand, several consecutivelyand firmly mounted pairs of rollers 11, 12 have to be disposed to takeup the forces arising from bending of the strand at the beginning of thecurved strand guiding means -1.

To simplify accompanying drawings, the guiding means were confined totwo faces (the upper and lower in FIG. 1) of the strand, whereas incertain cases it would be essential to have several consecutivelymounted guiding rollers arranged on the other faces as well.

What is claimed is: V

1. An improved strand guide for a continuous casting plant in whichliquid metal is poured into a cooled mold to solidify the periphery ofsaid metal into a skin enclosing a molten core and defining a strandwhich is withdrawn continuously from said mold and is further cooledafter it is withdrawn from the mold, which comprises roller guidemounting means positioned below the mold to receive the strand as it iswithdrawn from the mold, at least three roller pairs fixedly mounted onsaid roller guide mounting means, the first of said fixedly mounteroller pairs being positioned at the entrance to said mounting means,the second being positioned at the exit end of said mounting means, andthe third being positioned intermediate the entrance and exit of saidmounting means, a plurality of deflectable guide roller pairs, each ofsaid roller pairs comprising a first and second roller spaced apart by apredetermined fixed distance, a link coupling together said first andsecond spaced apart roller of each pair, a plurality of links couplingtogether a roller in each of said roller pairs with the correspondingroller of each adjacent roller pair, said links being pivotallyconnected to each of said rollers to form a chain link interconnectingsaid defiectable roller pairs, and links coupling the last of said chainof defiectable roller pairs to the respective rollers of the adjacentfixed roller pair, thereby to support said deflectable roller pairs andto provide a guide for guidance of said strand in which the respectivedefiectable roller pairs can deflect to a limited degree transversely tothe longitudinal axis of said strand.

References Cited J. SPENCER OVERHOLSER, Primaly Examiner.

o R. S. ANNEAR, Assistant Examiner.

